What is the expiation for sexual intercourse during the daytime in Ramadan for a couple if the wife was the one who initiated the foreplay?

The woman and her husband have committed a grave sin by intentionally breaking their fast during the daytime in Ramadan. They must make up for this day. The husband must also offer expiation (kaffarah), which is: freeing a believing slave; if he is unable, then fasting for two consecutive months; if he is unable, then feeding sixty poor people (approximately 1.5 kg for each poor person). It is more cautious for the woman to also offer expiation. Both of them must engage in sincere repentance and feel remorse for their actions.